I use a Razer Viper Ultimate mouse with FS2020 and it's been great for the most part.  Today, however, they ran an automatic update on the software (and its gaming optimizations).  As I was starting FS I noticed a small rectangular overlay had appeared in the sim window (upper left).  This appeared about halfway through the startup sequence, and stayed there, appearing over all menus and in the sim itself after I spawned at the departure airport.

The overlay was basically a clock with a frame counter: actual time, game time, and frames.  I really don't need this info and I especially don't want it in my flight window.  I can quickly check frames with the Game Bar or other tool when needed.  I tried to get rid of the thing (considering I had no idea where it had come from) but to no avail.  I finally gave up and decided to take my flight and figure it out later.  As I began pre-flight (CJ4 at KPDX on an overcast day) I noted that my frame rates were abysmal- running at 16-17 fps) and that everything was sluggish.  At this point I shut down the sim and tried to figure out what was going on.  I had already investigated the sim options to be sure something new hadn't been activated.  I also delved into all of the game bar options, nVidia options, etc and could find nothing.

It suddenly occurred to me that Razer had run an update - I started the Razer Central module but could find nothing.  Finally, I went into the Razer Cortex module, eventually making my way to the Game Booster, In-Game screen.  Sure enough, there was a new in-game Custom Display and it was active with all options turned on.  Basically, they did what I despise the most about some software developers: they updated without my permission, added an option with no warning, then activated that option without my permission.  After shutting this down I restarted FS and all was well - I was back at 30 fps at the airport and up to 40 fps in-flight.

So, if you have a Razer product, watch out for this one...

I have a Razer mouse but want nothing to do with its software.

Also have Razer Mouse, Keyboard, Headset. First thing before starting the SIM is to Check None of the Programms are running

I have left Razer Central running on Startup from the beginning to check charge levels, etc. and have never had issues.  They normally run updates on system boot-up and they're not an every day occurrence.  Overall, there haven't been disruptions and they've never interfered with running programs before.

This time they had turned on the new gaming overlay in the Cortex Gaming module (which I do not run)  Apparently they ran some "optimizing" procedures, then shut down Cortex but left the overlay operational.  I'll keep my eye on it.  If they do something like this again I'll see about removing Cortex from my computer.